The ISO 5631-2:2022 standard specifies a method for the determination of paper and Cardboard Color by diffuse reflection under outdoor daylight conditions (D65/10 °). This method is suitable for all kinds of paper and Cardboard including coated and uncoated paper, but not for fluorescence or metal pigments. The test uses Standard light source D65 and 10 ° viewing angle to evaluate Color characteristics by measurement of diffuse reflection light. This standard provides a uniform test method for Color quality control of paper and Cardboard, especially important in printing, Encasement and other industries.